Control systems, such as SCADA, PLC and DCS type systems are used for monitoring and controlling equipment and processes often in large factories or plants, such as manufacturing, mining and the like. Control systems allow an operator to easily view what is occurring with the equipment and/or processes, usually in real time and often in a simplified diagrammatic format. Control systems may also be referred to as alarm monitoring systems, and monitoring systems.
When used in shipping, control systems may sometimes be referred to as vessel monitoring systems, main engine monitoring systems, ballast (control) systems, power management systems, or the like. Control systems have a vast number of applications in diverse fields and industries.
If equipment or processes fail, or do not work at optimum capacity, then the control system is enabled to send an alarm which is received by the operator so that he or she can attend to rectifying a problem causing the alarm.
Fault finding of (mainly) electrical problems is frequently very time-consuming. This leads to a great deal of down time for a factory or the plant, which can be very costly. The fault resolution process, in one view, can be divided into two parts: determining of the location and nature of the fault, and fault rectification.
Fault rectification is normally fairly quick, but the time required for determining of the location and nature of the fault varies from, say, 15 minutes to days in some examples. The actual time for determining of the location and nature of the fault depends on the skills of a person tasked with fixing the fault, the tools that are available to that person and the complexity of the installation and the fault. Frequently, multiple disciplines are required to complete the fault finding process.
Some organizations compile a knowledge base of faults and their potential solutions, and combine this with the procedures to minimize time required for determination of the location and nature of the fault. The method still depends heavily on the available skills of the maintenance personnel involved with the fault finding.
This problem has, to date, not been solved because of the high level of customization (of the automation systems) that is needed to provide the required level of information and guidance to reduce the time for the location of the fault to a short, predictable and repeatable time.
Solving the above-mentioned problem is further complicated as there is no logical or logistical link between the entities that each contain part of a solution for dealing with determining of the location and nature of a fault. Each entity is typically created by tools from a different vendor.
Presently, most or all alarm conditions in a control system are displayed on a control screen of the control system (for example, a SCADA system screen or interface). The annunciated alarms (in this case, true alarms) are intended to alert an operator to a process or equipment problem that needs to be rectified, such as high temperature or high level, slow rotation, and other such process and/or equipment problems that can occur in a factory, a plant or the like. This type of rectification action commonly falls within the capabilities of operating or maintenance personnel.
As the alarm conditions are generated by sensors or contacts that are connected to the control system by means of cables and wires, it happens regularly that the sensors, contacts, wires, cables or their connections fail. Such a situation will generate a fault condition that does not exist (which may be a false alarm) and the location of the fault will need to be identified before rectification can occur. This sort of situation leads to long periods of time being spent in determining of the location and nature of the fault, as previously discussed. The cause of this type of problem is typically much harder to identify than, for example, problems in process or equipment.
Fault finding of problems in the control system, the input components, the output components and/or connections in wires and other items usually requires one or more personnel using a combination of skills and specialist knowledge or intuition to identify the fault location and nature.
Usually the fault finding process involves the following steps:
(1) Analysis of the annunciated alarm in order to identify how the alarm is generated and thus which inputs and outputs of the control system are associated with this alarm. This frequently requires specialist knowledge and tools that may or may not be available at the facility, being the factory or plant. This step can be a very time-consuming process;
(2) Determine the relevant drawing(s) in hard or soft copy. These drawings may be available at the facility, but may also be off-site. The time required for this step depends on the availability of the drawings, whether the drawings are well-indexed, how familiar the maintenance personnel is with the installation and the documentation, and may also depend on factors such as if the documentation has been properly catalogued and stored;
(3) Frequently additional information is required in the form of data sheets for equipment such as sensors and the like. Similarly to the process in step 2, the time required depends on such factors as data sheet availability, indexing, cataloguing, familiarity etc.; and,
(4) Only when steps 1, 2 and/or 3 have been completed can the real fault finding, identification and rectification of the process and/or equipment, or the input and/or output components and/or the control system begin.